JP2014137326A - Measuring apparatus and measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure grounding characteristics of a tire which runs on a road surface ice layer.SOLUTION: A measuring apparatus includes: a pressure sensor 34 which is embedded in a road surface ice layer 38; and a calculation part 36 which calculates a ground contact pressure, shearing stress in a width direction and the shearing stress in a circumferential direction of a tire 10 when signals are received from a pressure sensor 34 and the tire 10 runs on the road surface ice layer 38.

Description

  The present invention relates to a measuring device and a measuring method, and more particularly, to a measuring device and a measuring method for tire ground contact characteristics on an ice layer road surface.

  Conventionally, as a method of measuring ground contact characteristics such as tire contact pressure, width direction shear stress and circumferential direction shear stress during traveling, for example, a pressure sensor capable of measuring these is embedded in a test road surface of asphalt pavement, and a vehicle is mounted. There is a method of measuring the ground contact characteristics of a tire at the moment of passing over the pressure sensor by passing the pressure sensor (for example, refer to the background art of Patent Document 1).

JP 2011-203207 A

  However, tires may travel on various road surfaces, and the ground contact characteristics of tires change particularly on ice layer road surfaces as compared to asphalt road surfaces.

  In view of the above facts, an object of the present invention is to provide a measuring device and a measuring method capable of measuring the ground contact characteristics of a tire traveling on an ice layer road surface.

The measuring device according to the first aspect of the present invention includes a pressure sensor embedded in an ice layer road surface, a signal transmitted by the pressure sensor, and a tire contact pressure when the tire travels on an ice layer road surface, A calculation unit that calculates a width direction shear stress and a circumferential direction shear force.
According to this configuration, the calculation unit can measure the ground contact characteristics of the tire traveling on the ice layer road surface.

In the measuring device according to the second aspect of the present invention, in the first aspect, a plurality of the pressure sensors are arranged in the tire traveling direction at intervals, and the length of the pressure sensor in the tire traveling direction is 3.6 mm or less. It is.
According to this configuration, even for a tire in which the tire surface is divided into small blocks, such as a winter tire in which sipes are carved at intervals of 3.6 mm to 7 mm, the ground contact characteristics for each small block with respect to the ice layer road surface. Can be measured.

A measurement method according to a third aspect of the present invention provides the measurement device according to the first aspect or the second aspect, allows a vehicle to pass on the ice layer road surface, and a contact pressure of a tire mounted on the vehicle. The ground contact characteristics of the tire are measured by calculating the width direction shear stress and the circumferential direction shear force.
According to this method, the ground contact characteristic of the tire traveling on the ice layer road surface is measured.

  According to the present invention, it is possible to measure the ground contact characteristics of a tire traveling on an ice layer road surface.

It is a vertical direction sectional view of an ice layer road surface. It is a top view of the ice layer road surface shown in FIG. 1 is a tire radial direction cross-sectional view of a pneumatic tire according to an embodiment of the present invention. It is a vertical direction sectional view of a state where a water film is formed on the ice layer road surface.

  Hereinafter, a measurement apparatus and a measurement method according to embodiments of the present invention will be specifically described with reference to the accompanying drawings.

<Pneumatic tire>
First, a pneumatic tire that is a measurement target of the measurement device and the measurement method will be described. As shown in FIG. 3, a pneumatic tire (for example, a studless tire) 10 includes a carcass 12 composed of one layer or a plurality of layers, each end of which is folded by a bead core 11.

A belt layer 14 in which a plurality of belt plies are stacked is embedded on the outer side in the tire radial direction of the crown portion 12 </ b> C of the carcass 12.
A tread portion 16 provided with a groove is formed on the outer side of the belt layer 14 in the tire radial direction. A plurality of circumferential main grooves 22 are formed in the tread portion 16 along the tire circumferential direction.

  A land portion 24 is formed between the circumferential main grooves 22. Each land portion 24 is formed with a plurality of circumferential sipes 26 along the tire circumferential direction. The depth of the groove of the circumferential sipe 26 is in a range of 50% or more and less than 100% of the depth of the circumferential main groove 22.

  Further, as shown in FIG. 1, a plurality of width direction sipes 28 are formed in the land portion 24 along the tire width direction.

  Further, the land portion 24 is formed with a plurality of small blocks 30 surrounded by the circumferential main groove 22, the circumferential sipe 26, and the widthwise sipe 28. The length of the small block 30 in the tire circumferential direction, that is, the interval between the widthwise sipes 28 is 3.6 mm or more and 7 mm or less. The length of the small block 30 in the tire width direction, that is, the interval between the circumferential sipes 26 or between the circumferential sipes 26 and the circumferential main groove 22 is also set to 3.6 mm or more and 7 mm or less.

<Measurement device>
Next, the measuring apparatus according to the present embodiment will be described.

As shown in FIG. 1, the measuring device 32 according to the present embodiment includes a three-component force sensor 34 and a calculation display unit 36.
The three-component force sensor 34 has a disk shape and is embedded in the ice layer road surface 38 in a matrix-like arrangement in which a plurality of them are arranged in the tire running direction P and the tire width direction at intervals (see FIGS. 1 and 2). ).

  Each of the three component force sensors 34 has three levels of force in the tire circumferential direction, the tire width direction, and the ice layer road surface vertical direction that the ice layer road surface 38 receives from the pneumatic tire 10, that is, the circumferential shear stress of the tire, The width direction shear stress and the ground pressure are measured by the value of voltage change or electric resistance change.

  Further, the length of the pressure receiving surface 34A of each three component force sensor 34 in the tire traveling direction P is set to be equal to or less than the interval between the width direction sipes 28, that is, 3.6 mm or less. Similarly, the length of the pressure receiving surface 34A of each of the three component force sensors 34 in the tire width direction is set to be equal to or less than the interval between the circumferential sipes 26, that is, 3.6 mm or less. In the present embodiment, since the three-component force sensor 34 has a disk shape, the diameter of the pressure receiving surface 34A is equal to the length of the pressure receiving surface 34A in the tire running direction P and the length of the pressure receiving surface 34A in the tire width direction.

Each three component force sensor 34 is connected to one calculation display unit 36 by wire or wirelessly.
The calculation display unit 36 receives electric signals of voltage change and electric resistance change from each of the three component force sensors 34, and the ground pressure and width of the pneumatic tire 10 when the pneumatic tire 10 travels on the ice layer road surface 38. The directional shear stress and the circumferential shear stress are calculated (converted) for each of the three component force sensors 34. Then, the calculation display unit 36 displays the calculation result on the display screen 36A, or is connected to a personal computer (not shown) and displayed on the display screen.

<Measurement method>
Next, a measurement method according to this embodiment will be described.

First, the above-described measuring apparatus is prepared. That is, a plurality of three component force sensors 34 are embedded in the ice layer road surface 38 in a matrix.
Next, a vehicle equipped with the pneumatic tire 10 is passed over the ice layer road surface 38 in which the three-component force sensor 34 is embedded.
Then, when passing through the vehicle, the voltage change or the electric resistance change is measured by the three component force sensor 34 and converted into the ground contact pressure, the width direction shear stress and the circumferential direction shear stress of the pneumatic tire 10 by the calculation display unit 36. Displayed.

  As a result, the ground contact characteristics of the pneumatic tire 10 traveling on the ice layer road surface 38 can be measured.

  A plurality of the three component force sensors 34 are arranged in the tire traveling direction at intervals, and the length of the three component force sensors 34 in the tire traveling direction is 3.6 mm or less. Thus, for example, when the pneumatic tire 10 in which the width direction sipes 28 are cut at intervals of 3.6 mm to 7 mm and the tire surface is divided into small blocks travels on the ice layer road surface 38, the tire circumference with respect to the ice layer road surface 38 is increased. It is possible to measure the ground characteristics for each small block along the direction.

  Similarly, a plurality of three component force sensors 34 are arranged in the tire width direction at intervals, and the length of the three component force sensors 34 in the tire width direction is 3.6 mm or less. Thereby, for example, when the pneumatic tire 10 in which the circumferential sipe 26 is cut at an interval of 3.6 mm to 7 mm and the tire surface is divided into small blocks travels on the ice layer road surface 38, the tire width with respect to the ice layer road surface 38. It is possible to measure the ground characteristics for each small block along the direction.

<Modification>
As mentioned above, although several embodiment of the technique which this application discloses was described, the technique which this application discloses is not limited above.
For example, the pressure sensor according to the present embodiment has been described using the three-component force sensor 34 that detects only force components in three directions, but a six-component force sensor that simultaneously detects force components and moment components in three directions. Other sensors may be used.
Moreover, although the case where the plurality of three component force sensors 34 are connected to one calculation display unit 36 has been described, an individual calculation display unit 36 may be connected to each of the three component force sensors 34.
Further, in the present embodiment, the case where the pneumatic tire 10 travels on the ice layer road surface 38 has been described. However, as shown in FIG. 4, the ice on the ice layer road surface 38 melts and the air above the water film 40 flows. When the entering tire 10 travels, the viscous resistance of water can be measured by the three-component force sensor 34.

  Furthermore, it goes without saying that the technology disclosed in the present application can be implemented with various modifications within a range not departing from the gist thereof.

10 pneumatic tires (tires), 32 measuring devices, 34 tri-component force sensors,
34 three-component force sensor (pressure sensor), 34A pressure-receiving surface, 36 calculation display unit (calculation unit),
38 Ice layer road surface

Claims (3)

A pressure sensor embedded in the ice layer road surface;
A calculation unit that receives a signal from the pressure sensor and calculates a tire contact pressure, a width direction shear stress, and a circumferential direction shear force when the tire travels on an ice layer road surface;
Measuring device. A plurality of the pressure sensors are arranged in the tire running direction at intervals, and the length of the pressure receiving surface of the pressure sensor in the tire running direction is 4 mm or less.
The measuring apparatus according to claim 1.   A measurement device according to claim 1 or 2 is prepared, and the ground pressure, the width direction shear stress and the circumferential direction shear force of a tire passing through the ice layer road surface by a vehicle and mounted on the vehicle are calculated. To measure the ground contact characteristics of the tire.

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